Engaging in strenuous exercise causes the body to become depleted of water and electrolytes, requiring replenishment. If water and electrolytes are not replaced, symptoms of dehydration can occur.
Physical activity, such as exercise, particularly in the heat, places a great metabolic demand on the body. During exercise, fluid in the form of sweat, lost from the body, can produce a state of dehydration. Associated with dehydration is an impairment of body heat dissipation and endurance. Although body electrolytes are also lost through perspiration, the net concentration of electrolytes per unit volume of body fluid actually increases. This is because perspiration causes a proportionately greater loss of water in comparison to the loss of body electrolytes. In addition, physical activity places an extra demand on the body's carbohydrate stores, such as muscle glycogen, liver glycogen and plasma glucose. Loss of water, redistribution and loss of electrolytes and the depletion of endogenous carbohydrate stores are the primary causes of fatigue which impairs one's ability to perform.
With stores of carbohydrates replenished during physical exertion, fatigue can be overcome. To maintain the body's physical capabilities, it is essential that water, electrolytes, carbohydrates, as well as other nutrients be provided in a timely and appropriate manner. Fluid replacement during physical activity has been shown to be an effective way of preventing dehydration and allowing for top physical performance. Of significance is the fact that the sports drink prevents dehydration. Dehydration itself can produce cramping.
Different theories abound as to the cause of muscular cramping during exercise. One theory postulates that cramping is due to electrolyte imbalance; another holds physical exercise causes damage to muscular tissue; and still another theory holds that muscle cramping is brought on by oxygen radicals produced by the body during strenuous exercise.